Remote keyless entry ("RKE") systems are well known in the automotive industry. Comprising a fob transmitter for transmitting a remote control signal and a receiver for receiving each remote control signal, remote keyless entry systems enable users to control several vehicle functions remotely, such as the door locks and trunk, for example. By this design, each remote control signal comprises a functional command which the receiver initiates once the validity of the signal is determined.
In providing remote control to vehicle functions, a problem arises as to restricting remote access to the automobile's owners and authorized users. As the remote control signals are transmitted over the air, interception is a substantial and growing possibility as a means of gaining unauthorized access to the vehicle.
One solution which has been incorporated to defeat the simple retransmission of remote control signals is rolling code encryption. Here, each remote control signal is shifted and changed such that simple playback of the last transmitted remote control signal does not initiate a vehicle function because the previous signal is dissimilar to the present signal.
There are however other limitations irrespective of using rolling code encryption. These drawbacks primarily focus on the potential for simultaneous jamming and interception of the transmitted remote control signal. In one scenario, a thief simultaneously jams the reception of the remote control signal while also intercepting the remote control signal as transmitted by an authorized user. The authorized user, at such time, assumes a malfunction in the RKE system and enters the vehicle using the traditional key. The thief, as a result, follows the authorized user until the vehicle is parked and retransmits the intercepted remote control signal.
Thus, industry requires a method and system for preventing an unauthorized user from reproducing a remote control signal to gain access to a vehicle.